This invention relates to a dry adhesive for floor coverings and a process therefor. More specifically, the dry adhesive is an acrylic.
Polyvinyl chloride (PVC) cast solid and foamed films in varying thicknesses are used for many applications; particularly in the floor covering field. Most notably, these are found in the walk off mat industry, the fatigue mat industry, and the carpet backing industry. Being a true thermoplastic material PVC is characterized by memory and slow recovery to deformation as opposed to true cross-linked polymers like natural rubber and certain polyurethanes. The processing ease, chemical and environmental tolerances, versatility of properties and relative favorable economics make PVC a material of choice wherever possible.
In the normal joining of PVC foams and films to other substrates, the need often arises to post apply, or to delay application of one surface to the other. An example of this would be the installation of PVC backed carpet or carpet tiles over concrete or wood floors, wherein the floor preparation is often done ahead of time. The result is a tacky floor that is out of service. If the floor were to be tack free, then the floor could not only be waled on if needed, but also walked on during application of the PVC backed product. Floor tiles with a PVC back are normally installed by applying a pressure sensitive adhesive to various types of flooring, followed by a waiting period for the adhesive to dry followed by a cumbersome laying out of the tiles. If the adhesive is aggressive, moving and adjusting of the tiles is an obvious problem.
We have discovered that bonding PVC to a variety of materials, from cloth to concrete, is achievable by the simple laying of the PVC surface to the other surface without the use of conventional wet, tacky, intermediate layer or layers of conventional adhesives. A simple pre-application of a chemical intermediate to the second surface in latex form and dried to a nontacky state is done. This is followed in any length of time thereafter with the simple contact of both surfaces, one to the other. A mild to aggressive tack bond, or a hard permanent joining of both surfaces is achieved. This bond is formed by the polar attraction of certain acrylics to the plasticizers in the PVC. This surface to surface migration of the plasticizer can be made to happen rapidly; within hours.
The ability to make changes during installation; the ease with which materials and personnel can move about; are but a few of the advantages of this system. With our invention, the acrylic is applied to the floor by conventional means and methods using half of the amount needed for pressure sensitive adhesives. The thin coating dries within one hour and the floor can be walked on before and during the laying out of the tiles. Since it takes contact and some time, the tiles can be moved and adjusted. This method functions well in conjunction with some contact adhesives to temporarily keep the tiles in place as the bond is formed. Roll goods are easily installed with this technique.